Google’s John Mueller said in a hangout with webmasters at the 47:47 minute mark that if a site sees a big drop in a day or so in their Google rankings and others are complaining about a Google update then that is probably related to a change on Google’s end to their search ranking algorithm. John added that when you make site changes or technical changed, that generally those changes take weeks to months to impact the site and even so, it impacts the site over time slower than an algorithm update on Google’s end.

So if you make a change to how your URLs work and Google has to pick up all those 301s, that process happens slowly and your rankings won’t drop over night. It fluctuates and has a more long term impact over a longer period of time. You might see your traffic continue to drop over time if you did something wrong.

But if Google’s algorithm update on a specific day determines your site is not as good as it once was, then you will likely see that impact pretty quickly – over a day or so.

Now, this is a generalization, not all site technical changes take a long period of time – if you block your whole site from Google, that can be pretty quick. Also not all algorithms impact a site over night, we know some algorithms take time to roll out and only pick up signals on new crawl and processing.

Here is how Glenn summed it up:

But in general, it seems this is what John is saying. Here is the video embed:

Here is the transcript:

Forum discussion at Twitter.